The invention is particularly applicable to the delivery of materials such as medication, DNA, and tissue, and will be described in particular with reference thereto. It will be appreciated by those skilled in the art, however, that the invention has broader application and may be used for selective deposition of materials or selective extraction of tissue samples and the subsequent deposition of materials into living matter.
One type of biopsy needle which can be used in the present invention relates is a side cut needle such as the type commercially known as "Trucut" needles. Such a side cut needle includes a solid stylet telescopically received within an inner tubular cannula which in turn is telescopically received within an outer tubular cannula by which the stylet and inner tubular cannula are supported for axial and rotative displacement relative to one another and to the outer cannula. The side cut needle is inserted into a patient until the distal end of the outer cannula reaches the lesion where a biopsy specimen is to be taken. The stylet is then advanced relative to the outer and inner cannulas into the lesion to the biopsy site. The stylet is provided with a cutting recess in the distal portion thereof and, when the stylet reaches the biopsy site, the stylet is rotated so that a cutting edge of the cutting recess severs the tissue. The inner cannula is then advanced relative to the outer cannula and over the stylet to cut the tissue into the cutting recess and to cover the recess and thus entrap the specimen within the recess for removal from the site by retracting the stylet and inner cannula into the outer cannula and then withdrawing the needle from the patient.
In a number of my prior U.S. Pat. Nos. 4,708,147; 4,838,280; 4,936,835; 5,080,655; 5,195,988; 5,254,105; 5,330,445; 5,394,887; 5,447,502; 5,477,862; 5,487,392; 5,573,518; and 5,718,237, there is disclosed a side cut needle of the foregoing character in which the equivalent of the inner cannula referred to above is provided with a tubular sheath of a absorbable gelatin material or a non-bioabsorbable hemostatic collagen for minimizing bleeding of the patient from the biopsy site upon removal of the needle. In this respect, the hemostatic sheath is applied about the distal portion of the inner cannula and is advanced therewith into the lesion for the inner cannula to cover the cutting recess in the stylet which, as described above, is initially inserted into the lesion and rotated to sever a biopsy specimen to be removed from the lesion. In accordance with my earlier arrangements, the equivalent of the outer cannula referred to hereinabove is also inserted into the lesion and has a distal end adjacent the axially inner end of the hemostatic sheath for positioning the sheath in the location where the biopsy specimen was taken when the specimen is withdrawn therefrom. More particularly in this respect, when the biopsy specimen is cut and enclosed in the cutting recess as described above, the stylet and inner cannula are withdrawn or retracted relative to the outer cannula which is held stationary at the site, whereby the axially inner end of the sheath engages the outer cannula and is held in its position within the lesion as the inner cannula and stylet are retracted into the outer cannula. When the sheath is released from the inner cannula, the needle is withdrawn from the site of the lesion.
While the hemostatic sheath in my earlier arrangements served its intended purpose to minimize bleeding from the biopsy site by compressing the bleeding tissue surrounding the biopsy site and by swelling upon absorbing body fluid so as to increase the compressive effect, there were a number of disadvantages with respect to the structure and manipulation of the component parts of the biopsy needle in connection with obtaining a biopsy specimen.
These disadvantages were overcome in my later patents. The new biopsy needles were designed such that the distal portion of the inner cannula was provided with a recess which supports a hemostatic insert for displacement therewith into the biopsy site in conjunction with advancing the inner cannula over the cutting recess in the stylet of the needle following rotation thereof to sever a specimen at the site. Accordingly, when the needle is inserted in a patient's body to move the distal end of the distal portion of the outer cannula to a position adjacent the lesion, and the stylet is then extended relative to the outer cannula to penetrate the lesion and is rotated to sever a biopsy specimen therefrom, the inner cannula and the hemostatic insert supported thereon remain within the distal portion of the outer cannula, thus the hemostatic insert is advantageously protected from exposure to infectious micro-organisms prior to use and during use is protected from exposure to body fluids by the outer cannula during the needle inserting and specimen severing stages. The inner cannula and hemostatic insert arrangement minimized the diametrical dimension of the puncture in the lesion by the needle to that of the inner cannula in a standard side cut needle, thus to minimize the possibility of hemorrhagic complications. The biopsy needle also enables automated operation of the side cut needle through the use of well known "guns".
My biopsy needles disclosed in my previous patents provide an effective means for successfully obtaining tissue samples either by manual or automated techniques while reducing complications such with bleeding. However, there still exists a deficiency in the art relating to the delivery of a "cargo" to a specific site in the body. These "cargos" include, but are not limited to, gelform, angiographic coil, tissue, medication, DNA, or other like materials. In many medical techniques, it is essential to deliver materials to a specific site in the body. Many of these materials cannot be delivered by an injection, thus requiring surgery which is significantly more expensive, time consuming, and can be significantly more painful and lead to complications and infection.
Therefore, there is a need for a device that can efficiently and effectively deliver a variety of materials to a specific site in a body which reduces complications and bleeding and avoids the traditionally more evasive medical techniques.